The Waldenecksee or Petersee is a quarry lake on the western edge of the Northern Black Forest.

It lies in an exclave of the municipality of Sinzheim, surrounded by Baden-Baden, between Iberg and Fremersberg on the western side of the hill of Waldeneck.

This could only be prevented in summer 2013 by the intervention of the fire service who enriched the lake water by spraying it with oxygen.

[2] The rocks are lithostratigraphically part of the Lichtental Formation, which is composed of remains of a volcano that is almost 300 million years old.

[7][8] The terrain of the quarry and lake, which is about 2 kilometres from the Baden-Baden broadcasting studio of Südwestrundfunk is repeated used as a film location.